U.S. patent application number 11/882513 was filed with the patent office on 2008-03-06 for apparatus for and method of managing a routing table in a multi-hop system.
This patent application is currently assigned to Samsung Electronics Co. Ltd.. Invention is credited to Jong Ho Bang, Jin Woo Choe, Kil Su Hong, Dong Kun Kim, Sung Hyuk Lee, Yongsuk Park, Bong Jhin Shin.
Application Number | 20080056126 11/882513 |
Document ID | / |
Family ID | 39151349 |
Filed Date | 2008-03-06 |
United States Patent
Application |
20080056126 |
Kind Code |
A1 |
Park; Yongsuk ; et
al. |
March 6, 2008 |
Apparatus for and method of managing a routing table in a multi-hop
system
Abstract
A method of managing a routing table by interoperating with a
routing block and a radio resource management (RRM)/scheduling
block in a plurality of nodes of a multi-hop system, the method
including computing a traffic load rate of each path which
transmits traffic and updating the routing table with the computed
traffic load rate via the routing block; and updating a plurality
of metrics included in the routing table based on the traffic load
rate and information transmitted from a neighbor node via the
RRM/scheduling block.
Inventors: |
Park; Yongsuk; (Seoul,
KR) ; Choe; Jin Woo; (Seoul, KR) ; Bang; Jong
Ho; (Suwon-Si, KR) ; Shin; Bong Jhin; (Seoul,
KR) ; Kim; Dong Kun; (Seoul, KR) ; Lee; Sung
Hyuk; (Seoul, KR) ; Hong; Kil Su;
(Geumjeong-Gu, KR) |
Correspondence
Address: |
ROYLANCE, ABRAMS, BERDO & GOODMAN, L.L.P.
1300 19TH STREET, N.W., SUITE 600
WASHINGTON,
DC
20036
US
|
Assignee: |
Samsung Electronics Co.
Ltd.
Industry-University Cooperation Foundation Sogang
University
|
Family ID: |
39151349 |
Appl. No.: |
11/882513 |
Filed: |
August 2, 2007 |
Current U.S.
Class: |
370/230 |
Current CPC
Class: |
H04L 45/021 20130101;
H04L 45/124 20130101; H04L 45/122 20130101; H04W 40/02
20130101 |
Class at
Publication: |
370/230 |
International
Class: |
G08C 15/00 20060101
G08C015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 4, 2006 |
KR |
10-2006-0084717 |
Claims
1. A method of managing a routing table by interoperating with a
routing block and a radio resource management (RRM)/scheduling
block in a plurality of nodes of a multi-hop system, the method
comprising: computing a traffic load rate of each path which
transmits traffic and updating the routing table with the computed
traffic load rate via the routing block; and updating a plurality
of metrics included in the routing table based on the traffic load
rate and information transmitted from a neighbor node via the
RRM/scheduling block.
2. The method of claim 1, wherein the information includes a
multi-route metric for each target node transmitted from at least
one neighbor node.
3. The method of claim 1, wherein the plurality of metrics comprise
a multi-route metric, a link metric, and a route metric for each
target node which indicate an amount of resources used for traffic
transmission.
4. The method of claim 3, wherein the traffic load rate is
allocated for each of the paths based on the route metric.
5. The method of claim 4, wherein the traffic load rate decreases
when an amount of resources required for each of the paths
increases, and increases when the amount of resources required for
each of the paths decreases.
6. The method of claim 3, wherein the link metric corresponds to an
amount of resources required for a link comprising a certain hop
between the nodes, and is determined by a total traffic on the link
and a status of a wireless channel.
7. The method of claim 3, wherein the route metric comprises an
amount of resources required for a route comprising a certain hop
or multi-hops between the nodes, and is determined by the link
metric and the information transmitted from the neighbor node.
8. The method of claim 3, wherein the multi-route metric
corresponds to an amount of resources required for a multi-route
comprising a certain hop or multi-hops between the nodes, and is
determined by the route metric and the traffic load rate.
9. The method of claim 3, wherein the updating of the plurality of
metrics comprises: computing the link metric based on the traffic
load rate and updating the routing table with the computed link
metric; computing the route metric based on the computed link
metric and the information transmitted from the neighbor node, and
updating the routing table with the computed route metric; and
computing the multi-route metric based on the computed route metric
and the computed traffic load rate, and updating the routing table
with the computed multi-route metric.
10. A computer-readable medium of instructions for controlling a
routing block and an RRM/scheduling block in a plurality of nodes
of a multi-hop system to manage a routing table comprising: a first
set of instructions for controlling the routing block to compute a
traffic load rate of each path which transmits traffic and to
update the routing table with the computed traffic load rate; and a
second set of instructions for controlling the RRM/scheduling block
to update a plurality of metrics included in the routing table
based on the traffic load rate and information transmitted from a
neighbor node.
11. An apparatus for managing a routing table in a multi-hop system
which interoperates with a routing and an RRM/scheduling in a
plurality of nodes, the apparatus comprising: a routing block for
periodically computing a traffic load rate of each path which
transmits traffic, and for updating the routing table the computed
traffic load rate; and an RRM/scheduling block for updating a
plurality of metrics included in the routing table, based on the
traffic load rate and information transmitted from a neighbor
node.
12. The apparatus of claim 11, wherein the information includes a
multi-route metric for each target node transmitted from at least
one neighbor node.
13. The apparatus of claim 11, wherein the plurality of metrics
comprises a multi-route metric, a link metric, and a route metric
for each target node which indicate an amount of resources used for
a traffic transmission.
14. The apparatus of claim 13, wherein the traffic load rate is
allocated for each of the paths based on the route metric.
15. The apparatus of claim 14, wherein the traffic load rate
decreases when an amount of resources required for each of the
paths increases, and increases when the amount of resources for
each of the paths decreases.
16. The apparatus of claim 13, wherein the link metric corresponds
to an amount of resources required for a link comprising a certain
hop between the nodes, and is determined by a total traffic on the
link and a status of a wireless channel.
17. The apparatus of claim 13, wherein the route metric corresponds
to an amount of resources required for a route comprising a certain
hop or multi-hops between the nodes, and is determined by the link
metric and the information transmitted from the neighbor node.
18. The apparatus of claim 13, wherein the multi-route metric
corresponds to an amount of resources required for a multi-route
comprising a certain hop or multi-hops between the nodes, and is
determined by the route metric and the traffic load rate.
19. The apparatus of claim 11, wherein the plurality of nodes
comprises at least one of a base station, a relay station, a
multi-hop station, and a mobile station.
20. The apparatus of claim 11, wherein the RRM/scheduling block
adds at least one node to form another path, when an amount of
resources required for any one of the paths increases.
21. The apparatus of claim 11, wherein the RRM/scheduling block
removes at least one node included in a path, when the amount of
resources required for any one of the paths increases.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. .sctn.
119(a) of Korean Patent Application No. 10-2006-0084717, filed on
Sep. 4, 2006, in the Korean Intellectual Property Office, the
entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a wireless multi-hop
system. More particularly, the present invention relates to an
apparatus for and a method of managing a routing table in a
multi-hop system to effectively increase resource efficiency.
[0004] 2. Description of Related Art
[0005] The increasing demand for data transmission using wireless
communication systems has resulted in a great deal of research into
improving the efficiency of such systems. Particularly, the
following areas have been extensively researched: systems using
multi-channel schemes such as multiple-input multiple-output (MIMO)
and orthogonal frequency division multiple access (OFDMA) for
obtaining diversity gain, and multi-hop systems for increasing
resource efficiency by reducing electromagnetic wave loss.
[0006] For such systems, research focuses on routing methods for
wireless multi-hop environments as well as radio resource
management (RRM) methods. The RRM methods increase the diversity
gain of multi-channel systems and greatly enhance system
performance.
[0007] Those methods include three phase parallel scheduling/RRM,
cross-layer routing-scheduling, destination sequenced distance
vector-multi channel (DSDV-MC), multi-path distance vector
algorithm (MDVA), and interference-aware routing.
[0008] However, multi-hop systems according to the conventional art
apply RRM/scheduling to links comprising only single hops. Also,
the multi-hop systems according to the conventional art do not
reflect changes in resource efficiency depending on channel
allocation for a particular routing. Accordingly, wireless
resources may not be used as efficiency as feasible.
[0009] Accordingly, there is a need for multi-hop systems and
methods which apply RRM/scheduling to links comprising multi hops
and reflect changes in resource efficiency depending on channel
allocation.
SUMMARY OF THE INVENTION
[0010] Exemplary embodiments of the present invention address at
least the above problems and/or disadvantages and provide at least
the advantages described below. Accordingly, an aspect of exemplary
embodiments of the present invention is to provide an apparatus for
and a method of managing a routing table which adjust to an amount
of resources depending on a path allocation on the routing table by
interoperating with a routing and a radio resource management
(RRM)/scheduling in a plurality of nodes of a multi-hop system,
thereby increasing resource efficiency.
[0011] According to an aspect of the present invention, there is
provided a method of managing a routing table by interoperating
with a routing block and an RRM/scheduling block in a plurality of
nodes of a multi-hop system. The method includes computing a
traffic load rate of each path which transmits traffic and updating
the routing table with the computed traffic load rate via the
routing block. A plurality of metrics included in the routing table
are updated based on the traffic load rate and information
transmitted from a neighbor node via the RRM/scheduling block.
[0012] According to an aspect of the present invention, there is
provided an apparatus for managing a routing table in a multi-hop
system which interoperates with a routing and an RRM/scheduling in
a plurality of nodes. The apparatus comprises a routing block for
periodically computing a traffic load rate of each path which
transmits traffic and for updating the routing table with the
computed traffic load rate. An RRM/scheduling block updates a
plurality of metrics included in the routing table based on the
traffic load rate and information transmitted from a neighbor
node.
[0013] Other objects, advantages, and salient features of the
invention will become apparent to those skilled in the art from the
following detailed description, which, taken in conjunction with
the annexed drawings, discloses exemplary embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other objects, features, and advantages of
certain exemplary embodiments of the present invention will be more
apparent from the following detailed description, taken in
conjunction with the accompanying drawings in which:
[0015] FIG. 1 is a diagram illustrating a multi-hop system
according to an exemplary embodiment of the present invention;
[0016] FIG. 2 is a diagram illustrating an example of an
operational principle of a multi-hop system according to an
exemplary embodiment of the present invention;
[0017] FIG. 3 is a block diagram illustrating a node comprising a
multi-hop system according to an exemplary embodiment of the
present invention;
[0018] FIG. 4 is a flowchart illustrating a method of managing a
routing table in a multi-hop system according to an exemplary
embodiment of the present invention;
[0019] FIG. 5 is a diagram illustrating relationships of a
plurality of parameters according to an exemplary embodiment of the
present invention;
[0020] FIG. 6 is a diagram illustrating an example of concepts of a
plurality of metrics according to an exemplary embodiment of the
present invention;
[0021] FIG. 7 is a diagram illustrating a process of adding another
node according to an exemplary embodiment of the present invention;
and
[0022] FIG. 8 is a diagram illustrating a process of removing a
single node according to an exemplary embodiment of the present
invention.
[0023] Throughout the drawings, the same drawing reference numerals
will be understood to refer to the same elements, features, and
structures.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0024] The matters defined in the description such as a detailed
construction and elements are provided to assist in a comprehensive
understanding of the embodiments of the invention. Accordingly,
those of ordinary skill in the art will recognize that various
changes and modifications of the embodiments described herein can
be made without departing from the scope and spirit of the
invention. Also, descriptions of well-known functions and
constructions are omitted for clarity and conciseness.
[0025] A mobile station (MS) as used throughout the present
specification includes mobile communication devices, a public
switched telephone network (PSTN) terminal, a voice over Internet
Protocol (VoIP) device, a session initiation protocol (SIP) device,
a media gateway control (Megaco) device, a personal digital
assistant (PDA), a mobile phone, a personal communication service
(PCS) phone, a hand-held PC, a Code Division Multiple Access
(CDMA)-2000 (1X, 3X) phone, a Wideband CDMA phone, a dual band/dual
mode phone, a Global System for Mobile Communications (GSM) phone,
a mobile broadband system (MBS) phone, a satellite/terrestrial
Digital Multimedia Broadcasting (DMB) phone, and the like.
[0026] FIG. 1 is a diagram illustrating a multi-hop system 100
according to an exemplary embodiment of the present invention.
[0027] As shown in FIG. 1, the multi-hop system 100 according to an
exemplary embodiment of the present invention includes a base
station BS 110, a plurality of nodes 120, and a mobile station MS
130. In this embodiment, the plurality of nodes 120 corresponds to
multi-hop stations or relay stations. The multi-hop system 100 may
transmit traffic via a multi-hop or a multi-channel from the BS 110
to the MS 130. Accordingly, the multi-hop system 100 may have a
relatively wider range of service than the current range of
service.
[0028] The plurality of nodes 120 includes a plurality of
multi-hops between the BS 110 and the MS 130. The plurality of
nodes 120 may reduce dead zones through the plurality of
multi-hops, improve transfer rate, and increase the range of
service.
[0029] An operational principle of a multi-hop system described
above according to an exemplary embodiment of the present invention
is described in detail with reference to FIG. 2.
[0030] FIG. 2 is a diagram illustrating an example of an
operational principle of a multi-hop system according to an
exemplary embodiment of the present invention.
[0031] In a multi-hop system according to an exemplary embodiment
of the present invention, for example, when transmitting traffic
via a path A, an amount of resources required to transmit the
traffic increases along a curve a as the traffic increases as shown
in a graph of FIG. 2. Also, when transmitting the traffic via a
path B, the amount of resources required to transmit the traffic
increases along a curve b as the traffic increases as shown in the
graph of FIG. 2. In this instance, the amount of resources required
to transmit the traffic via the path A is comparatively less than
the amount of resources required to transmit the traffic via the
path B. Accordingly, a BS transmits the traffic to a MS via the
path A.
[0032] Then, when the transmitted traffic increases such that the
amount of resources required to transmit the traffic via the path A
is as much as the amount of resources required to transmit the
traffic via the path B, the BS interoperates with a routing and a
radio resource management (RRM)/scheduling to thereby distribute
the input traffic via the path A and path B. Accordingly, the BS
transmits the input traffic to the MS.
[0033] A plurality of nodes comprising a multi-hop system according
to an exemplary embodiment of the present invention is described in
detail with reference to FIG. 3.
[0034] FIG. 3 is a block diagram illustrating a node 300 comprising
a multi-hop system according to an exemplary embodiment of the
present invention. In this embodiment, the node 300 may be any one
of a base station, a multi-hop station, a relay station, and a
mobile station.
[0035] As shown in FIG. 3, the node 300 comprising the multi-hop
system according to an exemplary embodiment of the present
invention includes a routing block 310, an RRM/scheduling block
330, and a routing table 320.
[0036] The routing block 310 computes a traffic load rate of each
path which transmits periodically transmitted traffic, and the
traffic load rate is allocated for each of the paths. Also, the
routing table 320 is updated with the computed traffic load rate by
the routing block 310.
[0037] The RRM/scheduling block 330 computes parameters included in
the routing table 320 based on the computed traffic load rate and
information. In this embodiment, the information is transmitted
from a neighbor node. Also, the parameters of the routing table 320
are updated by the RRM/scheduling block 330.
[0038] A method of managing a routing table in a multi-hop system
according to an exemplary embodiment of the present invention is
described in detail with reference to FIG. 4.
[0039] FIG. 4 is a flowchart illustrating a method of managing a
routing table in a multi-hop system according to an exemplary
embodiment of the present invention.
[0040] As shown in FIG. 4, the method of managing a routing table
in a multi-hop system according to an exemplary embodiment of the
present invention comprises the following operations. In operation
S410, a link metric is computed. In operation S420, the routing
table is updated with the computed link metric. In operation S430,
a route metric is computed. In operation S440, the routing table is
updated with the computed route metric. In operation S450, a
traffic load rate is computed. In operation S460, the routing table
is updated with the computed traffic load rate. In operation S470,
a multi-route metric is computed. In operation S480, the computed
multi-route metric is updated to the routing table. Also, the above
described operations may be performed independently or in another
order depending on each node.
[0041] The method of managing a routing table in a multi-hop system
according to an exemplary embodiment of the present invention is
described in greater detail below.
[0042] The routing table may include a plurality of parameters, and
the parameters may include a target node, the multi-route metric,
the link metric, the route metric, the traffic load rate, and
information, which are described in detail with reference to FIG.
5. In this embodiment, the information is transmitted from a
neighbor node, and may include a multi-route metric of the neighbor
node.
[0043] FIG. 5 is a diagram illustrating relationships of a
plurality of parameters according to an exemplary embodiment of the
present invention.
[0044] As shown in FIG. 5, the plurality of parameters according to
an exemplary embodiment of the present invention includes a target
node, a multi-route metric, a link metric, a route metric, a
traffic load rate, and information which is transmitted from a
neighbor node. In FIG. 5, k designates a current node, j designates
a plurality of relay nodes which provide a multi-hop communication,
and i designates a target node. Also, L designates the link metric,
M, C designates the multi-route metric, and T designates the
traffic load rate. In this embodiment, the metrics correspond to an
amount of resources required for a traffic transmission, and
specifically refer to an average amount of resources used with
respect to unit information. For example, when the resource is a
number of channels with respect to a path for the traffic
transmission, a unit of the metrics may be the number of
channels/bit.
[0045] A method of computing the plurality of parameters defined
above is described in detail below.
[0046] The RRM/scheduling block 330 may update the parameters
included in the routing table 320 based on the traffic load rate
and the information. In this embodiment, the traffic load rate is
stored in the routing table 320, and the information is transmitted
from the neighbor node, i.e. the multi-route metric which is
computed in the neighbor node. The parameters may be computed by
equations detailed below.
[0047] The RRM/scheduling block 330 computes the link metric based
on the updated traffic load rate in operation S410. Also, the
computed link metric of the routing table 320 is updated by the
RRM/scheduling block 330 in operation S420. In this embodiment, the
link metric is determined by,
L k , j = f ( T .omega. k , .GAMMA. .omega. k ) T .PI. k = ( i = 1
NT - 1 T k , 1 , i D k , 1 , i , i = 1 NT - 1 T k , 2 , i D k , 2 ,
i , , i = 1 NT - 1 T k , N k , i D k , N k , i ) .GAMMA. .omega. k
= ( .GAMMA. k , 1 , .GAMMA. k , 2 , , .GAMMA. k , N k ) [ Equation
1 ] ##EQU00001##
[0048] Here, L.sub.k,j designates the link metric from the current
node k to the relay nodes j, and designates a vector indicating a
total amount of traffic which is transmitted from the current node
k via the relay nodes j. Also, designates a vector indicating a
status of a wireless channel connecting the current node k and the
relay nodes j. For example, when a status of a channel is
represented by a signal to interference and noise ratio (SINR), a
unit of the status of the channel may be in decibels (dB).
T.sub.k,j,i designates the traffic load rate from the current node
k to the target node i via the relay nodes j. D.sub.k,j,i,
designates an amount of traffic from the current node k to the
target node i via the relay nodes j. N.sub.k designates a number of
the relay nodes j connected with the current node k. NT designates
a total number of nodes which can be the target node i, i.e. the
total number of nodes comprising a multi-hop system. As described
above, a function f which has the traffic load rate T.sub.k,j,i as
a parameter may take into account the traffic load rate
T.sub.k,j,i, the total traffic to be transmitted to the target
node, and the status of the wireless channel. It should be noted
that the function f cannot be obtained in a closed form for most
practical multi-hop systems, and it is simply used to show that
L.sub.k,j depends on and . In practice, that the actual value of
L.sub.k,j can be computed by the RRM/scheduling block during its
normal operations.
[0049] For example, the RRM/scheduling block 330 simultaneously
performs an RRM and a scheduling with the traffic load rate
T.sub.k,j,i with respect to each link. As a result of performing
the RRM and the scheduling, a resource efficiency with respect to
an amount of resources, such as a cost, is reflected, and the link
metric is computed.
[0050] The RRM/scheduling block 330 computes the route metric
M.sub.k,j,i based on the updated link metric L.sub.k,j and the
multi-route metric C.sub.j,i which is transmitted from the neighbor
node in operation S430. Also, the computed route metric M.sub.k,j,i
of the routing table 320 is updated by the RRM/scheduling block 330
in operation S440. In this embodiment, the route metric M.sub.k,j,i
is determined by,
[0051] [Equation 2]
M.sub.k,j,i=C.sub.j,i+L.sub.k,j
[0052] Here, C.sub.j,i designates the multi-route metric from the
relay nodes j to the target node i, and is transmitted from the
neighbor node, i.e. the relay nodes j. M.sub.k,j,i designates the
route metric from the current node k to the target node i via the
relay nodes j, and may be computed by adding the multi-route metric
C.sub.j,i and the link metric L.sub.k,j.
[0053] In this embodiment, the routing block 310 computes the
traffic load rate T.sub.k,j,i of each path which periodically
transmits the traffic based on the computed route metric
M.sub.k,j,i in operation S450. Also, the routing block 310 updates
the computed traffic load rate T.sub.k,j,i to the routing table 320
in operation S460. That is, the routing block 310 decreases the
traffic load rate T.sub.k,j,i when an amount of resources required
for each of the paths increases, and increases the traffic load
rate T.sub.k,j,i when the amount of resources required for the each
of the paths decreases.
[0054] The routing block 310 increases the traffic load rate
T.sub.k,j,i of a path which has relatively higher resource
efficiency from among the plurality of paths transmitting the
traffic. Also, the routing block 310 may allocate traffic of the
increased traffic load rate T.sub.k,j,i to the path having
relatively higher resource efficiency.
[0055] The RRM/scheduling block 330 computes the multi-route metric
C.sub.k,i based on the updated route metric M.sub.k,j,i and the
updated traffic load rate T.sub.k,j,i in operation S470. Also, the
RRM/scheduling block 330 updates the computed multi-route metric
C.sub.k,i to the routing table 320 in operation S480. In this
embodiment, the multi-route metric C.sub.k,i is determined by,
C k , i = j = 1 N k T k , j , i M k , j , i [ Equation 3 ]
##EQU00002##
[0056] Here, C.sub.k,i designates the multi-route metric from the
current node k to the target node i, and may be computed by a sum
of values which are acquired by multiplying the route metric
M.sub.k,j,i and the traffic load rate T.sub.k,j,i.
[0057] The plurality of metrics described above is updated to the
routing table 320 as shown in Table 1.
TABLE-US-00001 TABLE 1 Target Multi-route node metric 1 . . . j 1
C.sub.k,1 T.sub.k,1,1 M.sub.k,1,1 L.sub.k,1 C.sub.1,1 . . .
T.sub.k,j,1 M.sub.k,j,1 L.sub.k,j C.sub.j,1 2 C.sub.k,2 T.sub.k,1,2
M.sub.k,1,2 L.sub.k,2 C.sub.1,2 . . . T.sub.k,j,2 M.sub.k,j,2
L.sub.k,j C.sub.j,2 . . . i C.sub.k,i T.sub.k,1,i M.sub.k,1,i
L.sub.k,i C.sub.1,i . . . T.sub.k,j,i M.sub.k,j,i L.sub.k,j
C.sub.j,i
[0058] As shown in Table 1, the plurality of parameters from the
current node k to the target node i via the relay nodes j for each
target node with respect to the relay nodes 1 through j are
included. In this embodiment, the plurality of parameters includes
C.sub.k,i, T.sub.k,j,i, M.sub.k,j,i, L.sub.k,j, and C.sub.j,i.
C.sub.j,i designates information transmitted from the relay nodes
j. The current node k transmits the multi-route metric C.sub.k,i
for each of the target nodes i from the routing table 320 to at
least one neighbor node. The routing table 320 described above is
not limited to the described embodiment, and may vary.
[0059] Concepts of the multi-route metric C.sub.k,i, the route
metric M.sub.k,j,i, and the link metric L.sub.k,j are described in
detail with reference to FIG. 6.
[0060] FIG. 6 is a diagram illustrating an example of concepts of a
plurality of metrics according to an exemplary embodiment of the
present invention.
[0061] As shown in FIG. 6, the link metric is an amount of
resources required for a link from among the plurality of metrics
according to an exemplary embodiment of the present invention. In
this embodiment, the link comprises a single hop between nodes. For
example, a link metric L.sub.1,2 designates a metric between a
current node 1 and a target node 2. The link metric L.sub.1,2 is
computed by a function which considers total traffic and a status
of a wireless channel as a parameter, similar to Equation 1. In
this embodiment, the traffic is transmitted via a relay node 2,
i.e. the target node 2, and the wireless channel connects the relay
node 2 and the current node 1.
[0062] Similarly, a link metric L.sub.1,3 designates a metric
between the current node 1 and a target node 3. The link metric
L.sub.1,3 is computed by a function which considers total traffic
and a status of a wireless channel as the parameter, similar to
Equation 1. In this embodiment, the traffic is transmitted via a
relay node 3, i.e. the target node 3, and the wireless channel
connects the relay node 3 and the current node 1.
[0063] The route metric is an average amount of resources used when
the traffic is transferred via a route. In this embodiment, the
route comprises a single hop or multi-hops between the nodes, i.e.
the route comprises one certain neighbor node to the target node.
For example, a route metric M.sub.1,2,6 designates a metric among
the current node 1, the relay node 2 and a target node 6. The route
metric M.sub.1,2,6 is computed by a sum of the link metric
L.sub.1,2 and a multi-route metric C.sub.2,6, similar to Equation
2.
[0064] Similarly, a route metric M.sub.1,3,6 designates a metric
among the current node 1, the relay node 3 and the target node 6.
The route metric M.sub.1,3,6 is computed by a sum of the link
metric L.sub.1,3 and a multi-route metric C.sub.3,6, similar to
Equation 2.
[0065] The multi-route metric is an average amount of resources
used when the traffic is transferred via a multi-route. In this
embodiment, the multi-route comprises a single hop or multi-hops
between the nodes, i.e. the multi-route comprises a plurality of
multi-hops to the target node. For example, a multi-route metric
C.sub.1,6 is a metric between the current node 1 and the target
node 6. The multi-route metric C.sub.1,6 is computed by a sum of
values. In this embodiment, the values are acquired by multiplying
a traffic load rate T.sub.1,2,6 and the route metric M.sub.1,2,6,
and a traffic load rate T.sub.1,3,6 and the route metric
M.sub.1,3,6, similar to Equation 3. Also, the traffic load rates
T.sub.1,2,6 and T.sub.1,3,6 are a traffic load rate for each path
via the relay nodes 2 and 3.
[0066] According to an exemplary embodiment of the present
invention, a routing and an RRM/scheduling are interoperated by
taking into account a change of a resource efficiency in the
plurality of nodes. Thus, network congestion may be reduced,
resource efficiency of the network may increase, and the network
may be stabilized.
[0067] The plurality of nodes are required to update the routing
table with each of the target nodes, and share the updated routing
table with a plurality of neighbor nodes. For this, a method has
been proposed that a routing table including only the multi-route
metric for each of the target nodes, not all routing tables, is
transmitted to the plurality of neighbor nodes. Thus, according to
this method, overhead for routing table transfer due to an increase
in size of the routing table may be reduced. For example, in Table
1, the multi-route metric C.sub.1,6 for each of the target nodes 1
though j may be transmitted to at least one neighbor node.
[0068] As described above, according to an exemplary embodiment of
the present invention, the routing and the RRM/scheduling are
interoperated by taking into account the change of the resource
efficiency in the plurality of nodes. Thus, a control function
which is required to be provided by a base station may be
distributed, and the control function of the base station may be
reduced.
[0069] Also, according to an exemplary embodiment of the present
invention, when adding or removing at least one other node to or
from the neighbor node, the apparatus for and method of managing a
routing table may be utilized, as described in detail with
reference to FIGS. 7 and 8.
[0070] FIG. 7 is a diagram illustrating a process of adding another
node according to an exemplary embodiment of the present
invention.
[0071] As shown in FIG. 7, a multi-hop system according to an
exemplary embodiment of the present invention may transmit traffic
via a path A to a mobile station MS. In this embodiment, the path A
is from a current node 1 to a target node 3 via a relay node 2. The
RRM/scheduling block 330 may add a node 4 included in another path
B, when an amount of resources required for the path A increases
and at least one parameter of the plurality of parameters, i.e.
C.sub.k,i, M.sub.k,j,i, and L.sub.k,j increases to be over a
predetermined level. For example, when the node 4 having a
signal-to-noise ratio (SNR) which is greater than a predetermined
threshold exists, the RRM/scheduling block 330 may add the node 4
to a neighbor node. Also, when a resource efficiency of path B
including the node 4 is greater than a resource efficiency of path
A, a portion of the traffic which is transmitted via path A may be
transmitted via path B.
[0072] Accordingly, the traffic may be transmitted to the MS via
the two paths, i.e. path A and path B. Specifically, path A is from
the current node 1 to the target node 3 via the relay node 2, and
path B is from the current node 1 to the target node 3 via another
node.
[0073] FIG. 8 is a diagram illustrating a process of removing a
single node according to an exemplary embodiment of the present
invention.
[0074] As shown in FIG. 8, a multi-hop system according to an
exemplary embodiment of the present invention may transmit traffic
to a mobile station MS via a path A and a path B. In this instance,
tpath A is from a current node 1 to a target node 3 via a relay
node 2, and path B is from the current node 1 to the target node 3
via a relay node 4. The RRM/scheduling block 330 may remove the
node 4 that forms path B when an amount of resources required for
path B increases and at least one parameter of the plurality of
parameters, i.e. C.sub.k,i, M.sub.k,j,i, and L.sub.k,j increases
over a predetermined level. For example, when a SNR of the node 4
from among neighbor nodes is less than a predetermined threshold
due to a situation change of the network, a resource efficiency of
a route including the node 4 decreases, and a traffic load rate
becomes `0`. Accordingly, the RRM/scheduling block 330 may remove
the node 4.
[0075] Thus, the traffic may be transmitted to the MS via the path
A, i.e. from the current node 1 to the target node 3 via the relay
node 2, by interoperating with the routing and the
RRM/scheduling.
[0076] The multi-hop system according to exemplary embodiments of
the present invention may be used in a wireless communication
system. Also, the multi-hop system according to exemplary
embodiments of the present invention may be used in a wired
communication system and a communication system combining the
wireless communication system with the wired communication system
regardless of the routing and the RRM/scheduling which are operated
for each hop or node.
[0077] The exemplary embodiments of the present invention may be
recorded in computer-readable media including program instructions
to implement various operations embodied by a computer. The media
may also include, alone or in combination with the program
instructions, data files, data structures, and the like. The media
and program instructions may be those specially designed and
constructed for the purposes of the present invention, or they may
be of the kind well-known and available to those having skill in
the computer software arts. Examples of computer-readable media
include magnetic media such as hard disks, floppy disks, and
magnetic tape; optical media such as CD ROM disks and DVD;
magneto-optical media such as optical disks; and hardware devices
that are specially configured to store and perform program
instructions, such as read-only memory (ROM), random access memory
(RAM), flash memory, and the like. The media may also be a
transmission medium such as optical or metallic lines, wave guides,
etc. including a carrier wave transmitting signals specifying the
program instructions, data structures, etc. Examples of program
instructions include both machine code, such as produced by a
compiler, and files containing higher level code that may be
executed by the computer using an interpreter. The described
hardware devices may be configured to act as one or more software
modules in order to perform the operations of the above-described
embodiments of the present invention.
[0078] According to an aspect of exemplary embodiments of the
present invention, an apparatus for and a method of managing a
routing table adjusts an amount of resources depending on a path
allocation to the routing table by interoperating with a routing
and a radio resource management (RRM)/scheduling in a plurality of
nodes of a multi-hop system, thereby increasing resource
efficiency.
[0079] While certain exemplary embodiments of the invention have
been shown and described with reference to certain preferred
embodiments thereof, it will be understood by those skilled in the
art that various changes in form and details may be made therein
without departing from the spirit and scope of the invention as
defined by the appended claims and their equivalents.
* * * * *